Television



C. D. FAHRNEY June 14, 1932..

TELEVISION Filed March l1, 1929 8 Sheets-Sheet l .ll/ffiiPfl/151115515541' June 14, 1932. c. D. FAHRNEY TELEVISION Filed Marchl1, 1929 8 Sheets-Sheet 2 June 14, 193.2l

C. D. FAHRNEY TELEVIS ION Filed March 11, 1929 Vlg@ 8 Sheets-Sheet 5June 14, 1932. C, D- FAHRNEY 1,862,743

TELEVISION lFiled March. 11, 1929 s sheets-sheet 4 AT TURN au;

Jllne 14, 1932. C, D, FAHRNEY 1,862,743

TELEVI SION Filed March 1l, 1929 8 Sheets-Sheet 5 June 14, 1932. C, 4DFAHRNEY 1,862,743

TELEVISION 8 Sheets-Sheet 6 Filed March ll, 1929 HENTQR:

qfe/KM/M AT1-GENE* June 14, 1932. c. D. FAHRNEY TELEVISION Filed March11. 1929 8 Sheets-Sheet 7 June 14, 1932. c. D. FAHRNEY 'mmasvlslonlFiied March 11, 1929 8 Sheets-Sheet 8 vNu Patented June 14, 1932 PATENTGALLO FAHRNEY, OF CAMBRIDGE, MASSACHUSETTS TELEVISION Application filedMarch 11, 1929.

The principal object of the present invention is to provide a televisionreceiving system, by means of which a relatively large picture will bereproduced by means of a comparatively small and compact scam'iingapparatus. Other objects of my invention are to provide the scanningapparatus with an improved reflector and with a more efficientpicture-receiving surface than those now in use. A further object of myinvention is to provide means for increasing the amount of lighttransmitted through the scanning apertures to the picture-receivingsurface. Other objects of my invention will hereinafter appear in thedetailed descriptionof the specific embodiments of my invention which Ihave employed to illustrate the principles thereof.

TvVith the foregoing objects in view, my invention comprises, as itssalient features, two rotating surfaces of revolution, such as twoconcentric cones or two concentric drums, provided with co-operatinglight-transmitting apertures, together with means for rotating saidmembers in the same direction at different speeds or in oppositedirections. rhe lamps, the luminosity of which s varied by the incomingcurrent, neon lamps for er:- ample, may be stationary, or may rotatewith one of said surfaces of revolution. In cases where the said lampsare stationary I may employ one such lamp placed either directly behindthe Window of the apparatus, or placed behind and forwardly of the same;or alternatively, since there is a limitation to the size of such lamps,I may use two neon lights placed behind and on either side of thewindow, together with a reflector such as a concave mirror whereby thelight rays are directed to the window, with or without the interpositionof a ray-concentrating means, such as a lens.

My invention contemplates also the use of a concave mirror as apicture-receiving surface.

My invention consists further in the parts and combination of partshereinafter more fully described and set forth in the appended claims.

Various illustrative embodiments of my in- Serial No. 345,978.

vention are shown in the drawings which accompany and form a part ofthis specification, but it is to be understood that said drawings aremerely illustrative and are not to be regarded as restrictive.

In the drawings- Figure l is a longitudinal central section of atelevision-receiving apparatus embodying my invention;

Fig. 2 is a similar fragmentary view of a modification;

F ig. 3 is a central longitudinal section of a television-receivingapparatus in which two lamps placed on either side of the window areemployed;

Fig. at is a front view shown in Fig. 3;

Fig. 5 is a central section of a further modiication in which the lampis placed behind and forwardly of the window;

Fig. 6 is a central section of a modification in which the lamps rotatewith one of the co-operating scanning members;

Fig. 'i' is an end view of the apparatus shown in F ig. 6;

F ig. 8 is a similar view of a further modii'ication in which therelative positions of the scanning' members are reversed from thoseshown in Fig. l;

Fig. 9 is a development on a smaller scale of the conical scanningmembers shown in Fig. l;

Fig. l0 is a fragmentary view showing a development on a larger scale ofthe ning members shown in Fig. l;

F ll is a development of the inner scann ning member shown in Fig. 6,and

F ig. l2 is a development of the outer scanning member which co-operatestherewith.

In the particular drawings selected for illustrating the principle of myinvention, 5() represents one of two co-operating scanning members,shown in the present instance as a cone, although as indicated at 5l inFig. 2, this member may be a surface of revoluanother form, such as acylinder. he

of the apparatus tion of co-operating scanning member is a cone 52concentric with the cone 50 in Fig. l and the cylinder or drum 53 inFig. 2. The inner member 52 is mounted on and rotates with the shaft 54of the motor 55, while the outer member is mounted loosely 'on saidshaft and is rotated in the same direction as the inner member but at alower speed, the gearing 56, 57, 58 and the pinion 59 meshing with theannular gear 60, which is rigidly attached to the member 50', serving todrive the latter at a lower rate of speed than the member 52.

The cone 52 is provided with a plurality ot perforations 6l which may becircular, as shown, or rectangular, as indicated in Fig. l0, and saidpertorations are arranged spirally around the periphery of the coneforming in the present instance Vtour spiral convolutions, thepertorations of the several spires being arranged in four rows, eachalong a generatrix of said surface. In the present instance, I showforty-eight perforations forming tour spirals of twelve perforationseach, although it will be understood that I do not limit myself in thismanner. he arrangement of the pertorations in the cylinder 53 isidentical with that above described in connection with the cone 52. Thecone 50 is provided with two light-transmitting apertures, shown, inthepresent instance, as the slots 62, each extending ap proximatelyone-half way around the periphery ot said cone in a diagonal directionand arranged to co-operate successively vwith the perforations 6l. Therelative position ot the said perforations and slots is shown in F ig. 9which is a development of the two cones 50, 52.

The preferred design is shown in Fig. lO in whichthe perforations arerectangular, preferably square, and the slots each consist of aplurality oi' contiguous rectangular sections 63, each displaced along ageneratrix of the cone by a distance equal to the width of one of theperiorations. A source ot light, the luminosity ot which is capable ofbeing varied by changes in the received current, such for example as aneon light in lamp 64, is provided for transmitting light through theapertures formed when the 'pen orations and slots are in register and,as shown in Fig. l, said lamp is placed behind theA window 65 throughwhich the transmitted light passes and impinges upon thepicture-receiving surface G6, a lens 6"? being interposed between saidlamp and window if desired. The lamp is supported by the adjustablebracket GS and the casing 69 in which the above described apparatus ishoused may be provided with a sliding door 70.

The motor being synchronized with the motor which drives thetransmitting scanning-disc the changes in luminosity of the lampeliected by variations in the electrical energy transmitted by wire orby yradio waves will vary the light units transmitted to thepicture-receiving surface 66 as the slots register successively with theperforations in the inner cone, and thereby compose the picture whichwas analyzed at the sending station by the scanning transmitter.

Referring to Figs. 9 and l() which lshow the relation between the slotsand pertor tions in more detail than can be indicated in Fig. l, thecones 50 and 52 are assumed to be rotating in the direction oi thearrows placed above said Figs. 9 and l0, respectively, and the innerperitorated cone, in the present instance, has a speed of rotation eighttimes higher than that oi 'the outer slotted cone. The perforation iShas just passed beyond the window located Vin dotted lines at G5, andthe perforation l is about to enter the ield oit said window. `When theperforation 4S was within the window, it was in register with the loverend of the leithand slot 62 and light was being transmitted through saidperforation is and slot.

As soon as the perforation .8 passes beyond the window, the perforationl in register with the upper end of the righthand slot (i2 passes intothe window and light from Va neon iainp is transmitted therethrough. Assoon the perforation l passes without the .ield ot the window theperforation will pass within the saine and will be in register with therighthand slot (32, and so on until the pertorations 2, il, et, 5 and (ihave swept by Vthe .\.'indo\.v, each being successively in register witha ditlerent portion of the righthand slot G2 in its pas' e thereacross,whereupon the identical aciion 'takes place with respect to theperforations T to l2, respectively, and the leithand slot G2, theaioresaid action taking place in one complete revolution et the cone 52.On the second revolution the perforations ,i3 to 24C pass across thewindow, sweeping `the two slots successively, and on the next tworevolutions of the cone, the perliorations 25 to 3G and 3T to 4S,respectively, pass across the window and sweep the said slots.

Referring particularly to Fig. l0, it will be noted that the endportions of the two slots overlap a distance equal, approximately, toseven-eighths of the width et the window, and also that the squareperforation l in the cone 52 which, as aforesaid traveis eight times.tast r than the cone 52, is in register with the upper righthand .endot the slot G2 in its passage across the window, Athe upper boundary 7iof the righthand end ot said slot being the are oi a circle ternir-d bythe intersection et said cone and a plane normal to the axis thereof.lVhen the .perforation l has ust passed without the window and therighthand end T2 ot the. siot is under the righthand boundary ot saidwindow, the rectangular section T3, which in length is equal toone-eighth of the width oi the window, is partly within the latter, asindicated by the dotted line 73, and the pei-fon tionr2 has just comeinto register with the 'iii vze

lefthand end of said section, being at this instant about to enter thefield of the Window as indicated by 2. y In like manner, the perforation 3 is in register With the section 74 just before it enters thefield of the Window, as indicated at 3. The positions of theperforations 4, 5 and 6 as they are about to enu ter the field of theWindow successively are shown at 4, 5l and 6', respectively, the saidperforations being in register, respectivelyv With the sections 7 5, 76and '.77 of the slot 62 as they successively7 pass across the Window.

It Will now be apparent that by means of the foregoing construction I amenabled to produce with a comparatively small and compact scanningapparatus, a much larger picture than could be composed by the scanningdiscs noiv in use. Specifically, by means of a cone 52 having its largerbase twelve i nches in diameter, and provided With forty-eight holesarranged as shown, and a concentric slotted disc 50 rotating atone-eighth the speed of the perforated disc, I am. enabled to compose athree inch square picture, using perforations of approximate-lyone-sixteenth inch in diameter, Whereas if a scanning` disc wereemployed to produce a picture of that size, such disc Would have to beforty-eight inches in diameter and have forty-eight perforationsarranged in a single spiral, each perforation being one-sixteenth inchin diameter. A standard scanning disc of the type novv generally in usein television reception and provided with forty-eight perforationsarranged in a single spiral, each perforation being one-thirty-secondinch in diameter, Will produce a picture only one and one-half inchessquare.

By means of the present invention I am enabled to use one-sixteenth inchperforations which permit the transmission of more light than thestandard twenty-four inch disc apparatus with one thirty-second inchperfon rations. Manifestly, a forty-eight inch disc would beprohibitively large and while a. three inch square picture could beproduced on a` twenty-four inch disc by reducing the number ofperforations from forty-eight to twenty-four, the resulting pictureWould lack detail.

T ie relative speeds of the two cones are determined by the number ofrows of perforations and the number of slots. If it were possible to usea. single slot extending all the Way around the cone, the ratio of thespeed of the perforated cone to that of the slotted cone would be fourto one; in the present instance it is eight to one, and if four slotsequally spaced around the cone Were used, such ratio would be sixteen toone. Thus the ratio of the speed of the perforated member to that of theslotted member is the ratio of the product of the number of rows of saidperforations by the number of slots to unity. i y

lVhere the surfaces of revolution which form the (1o-operating scanningmembers are cones, as in Fig. l, the standard disc transmitter may beused, but Where, as in the case of Fig. 2, such surfaces of revolutionare cylinders or drums, a drum transmitted must be employed. Theoperation of the apparatus shown in Fig. 2 is identical with that aboveset forth in Fig. l.

There being at present a limitation to the size of suitable lamps foruse in televisionreceiving apparatus, I have devised means forincreasing the amount of light transmitted through the scanning memberswhich consists in using a plurality of lights, one or more being placedon either side of the Window, together With means for directing thelight thereto.

In Figs. 3 and 4 I have illustrated a receiving system in which tivosuch lights 'i' 8, 7 8 are employed, one on either side of the Window65, although of course it is to be understood that a number of lightsconnected in multiple may be placed on either side of the Window. Thelight emanating from said lamps is directed by any suitable refiect-orsuch as the concave mirror 79 to the Window, and if desired a lens 8Omay be interposed between said reiiector and Window. The light-receivingsurface shown in Figs. 3 and 4 is a concave or magnifying mirror 8l,although it will be understood of course that the plane surface G6 shownin Fig. l may be used With the apparatus illustrated in Fig. 3, andconversely, and in general that such con cave or magnifying mirror maybe employed in any of the several embodiments of my invention.

In Fig. 5 the lamp 82 is not placed directly behind the Window i5, butis located behind and forwardly of the same, and the light from saidlamp is directed to the Window bv the reflector 79. L

The operation of the apparatus shown in Figs. 3, 4 and 5 will be readilyunderstood from the foregoing detailed description of the operation ofthe system shown in Fig. l.

In Fig. 8, the tWo co-operating scanning members 50 and 52 are made torotate in op` posite directions by mounting the outer member 52 torotatewith the shaft 54, and by mounting the inner member 50 loosely on saidshaft and connecting it therewith by the pinion 83, carried by androtating With said sha-ft, the gear 84 and the annular gear 85 by whichsaid inner member is carried, a sui"- able bracket 86 being provided tosupport the outer end of the shaft 54 and the stud 87 which carries thegear 84.

It Will be noted that the relative position of the perforated andslotted members is the reverse of that shown in Fig. l, although itvvill be understood of course that in this embodiment of my invention,as Well as that shown in Fig. l, the slotted member may be outside theperforated member. In like man- ,50 parallel thereto.

ner, it is immaterial whether the=sl0tted2member of Fig. 1 Abe disposedoutside the @perforated member, as showmor inside y.the same insofar as`the actual production of the 'picture `is concerned, but under lcertaincircumstances it may be preferable to Ahave said slotted member arrangedinside the iperforated member when both membersrota'te in the samedirection .and atdifferentspeeds.

In the case of Fig. 8,'the scanning member at the transmitting stationmust be `rotated oppositely to that of the scanning member used totransmit to the receiving apparatus shown in Fig. 1; :and in such casethe light units will .travel across the `window .or frame from thebottom up Iinstead of ffromthe .top down. In Fig. 8 I have indicated al.lens 188 interposed between the lamp and the window.

In order `to .further increase the :sizeof the received picture and alsolto make :it possible to reduce the size of the lamp without loss intransmitted light and thereby eifectza saving of electrical energy, Ihave devised a ireoei-v ing system in which a `plurality of lamps arecarried by and rotate with `the more slowly moving of the two(2o-.operating scanning members. One embodiment ofithis system :is shownin Figs. 6 and 7 vin which the outer or more rapidly Arotating scanningmember 89, herein shown as a cone, is mounted on and rotates with theshaft 54 and the inner cooperating member 90 is Iloosely mounted on saidshaft and rotated `oppositely Vto that of the member 89 by the pinion91, spur gears 92 and annular gear-98, the latter Ebeing secured to thevmember 90-in any suitablemanner. Brackets 94 attached to and rotatingwith the inner member 90 carry relatively small neon lamps 95, hereinshown as twelve in number, .and said lamps Aareenergized by currentsupplied through the 'brushes 96 which make contact with the rings '97carried by, but insulated from, the plate 98 to which the annular gearand cone 90 are secured. The cone '90 is Aprovided with a plurality `ofslots 99, herein shown as twelve, one for each lamp and said slots arearrangedalong generatrices-of the cone lin the present instance, eachlamp being disposed directly behind one rof said slots 4with its platesubstantially The co-operating .cone 89 has a plurality of arcuate slots91 .which are so disposed, as indicated in Fig. 11,.thattherespective-ends of each said slot terminates at the inner and outer endsof two o'f the contiguous apertures 99. The .arrangement :is such that.when the two scanningmembers-are rotating in the direction indicated'by fthe arrows in Figs. 11 and 12,'thespeed of rotation ofthe'outermember 89 with respect to the inner member 90 must be such :that one ofthe arcuate slots will vtraverse-onefof'Ethic slots 99 inthe timerequired-by the 'latter to move :a distance equal ,to its own width, :sothat as the slots .99 ymove successively ,across means the window, reachbeing swept as aforesaid by=one ofthe arcuate slots, the variable lightvalues transmitted through those portions of the respective pairs ofapertures 91, 99 which are in register will pass through the window andimpinge upon the mirror 65, thereby forming or composing the pictureanalyzed and sentout :at .the transmitting station.

It is .to be understood of .course that the analyzing apparatus at thetransmitting station must conform `to the .receiving apparatus shown inFigs. v6 and 7 insofar as the (io-operating light-transmittingaperturesare concerned, that is to say, such analyzer must consist v.oftwodiscs or two cones,or two other (zo-operating surfaces, providedrespectively with lightftransmitting apertures conforming in shape andarrangement with those used inthe receiving system.

In the .system shown in Fig. l .in which a single stationary light isused, the perforations which ,for convenience of representation aresomewhat exaggerated are in .the present instance only one forty-eighthofthe width of the window, and even if a lamp were used having a plateas wide as the window, only one forty-eighth of its area would beeective `in transmitting light through two registering apertures.However, in the system of Fig. 6, small lamps each having a long narrowplate can .be used, `the dimensions of such fplate being substantiallyco-extensive with a slot 99, and in this manner the cost both of thelamps and of the current necessary to energize :the same is greatlyreduced. In addition :to this advantage, a comparatively large picturemay be made with a relatively small and compact apparatus.

VThe :length ofthe picture will be that of one vof the slots 99 .and thewidth thereof will be equal to the ydistance between two such slots, and'.thus it will be seen that by properly correlating 'the -dimensions andpositions of the-slots with the rotational speeds of the respectiveco-operating members, a picture can `be formed larger than that possiblewith the apparatus of Fig. 1, other things being equal, and also that apicture equal to that made by .the apparatus of Fig. 1 can be formed bythe system of Fig. 6 more economically because, as ,above explained,smaller lamps consuming less energy may be used.

Having thus described various illustrative embodiments of my inventionwithout however limiting 'the same thereto, vwhat I claim and Vdesire tosecure by Letters Patent is 1. Ina television receivingapparatus, thecombination of a pair of drums one located within'theother and both.rotatable on pa-rallel axes,'the surface of one drum having a pluralityof circumferentially spaced lighttransmitting apertures arranged in aplus rality ofspira'ls, and the surface ofthe other drum having yaplurality of light-transmitting slots, and-means to rotate said drums atsuch relative speed that said slots cooperate with successive spirals ofapertures.

2. A television receiving apparatus com` prising in combination asurface of revolution provided with a plurality of rows of perforationseach arranged along a generatriX of said surface, the said perforationsbeing disposed around the said surface in such manner as to form aplurality of spirals, a co-operating concentric scanning member`provided with a plurality oit slots, and means for rotating saidsurfaces inv the same direction at relatively dierent speeds, the ratioof the speed of the perforated member to that of the slotted memberbeing the ratio of the product of the number of rows of saidperforations by the number of said slots to unity.

3. In a television receiving apparatus, scanning members provided withco-operating light-transmitting apertures, a window7 a lamp disposedbehind said window, and a magnifying mirror for receiving the lighttransmitted through said apertures when in registration.

In testimony whereof, I have hereunto subscribed my name this 5th day ofMarch, 1929.

GALLO D. FAHRNEY.

